Upright vacuum cleaners are well known in the art. Typically, these vacuum cleaners include an upper housing pivotally mounted to a vacuum cleaner foot. The foot is formed with a nozzle opening defined in an underside thereof and may include an agitator mounted therein for loosening dirt and debris from a floor surface. A motor and fan may be mounted to either the foot or the housing for producing suction at the nozzle opening. The suction at the nozzle opening picks up the loosened dirt and debris and produces a flow of dirt-laden air which is ducted to the vacuum cleaner housing.
In conventional vacuum cleaners, the dirt-laden air is ducted into a flexible filter bag supported on or within the vacuum cleaner housing. Alternatively, bagless vacuum cleaners duct the flow of dirt-laden air into a dirt separation system having a dirt cup which filters the dirt particles from the airflow before exhausting the filtered airflow into the atmosphere. A drawback to bagless cleaners is that the flexible filter bag tends to muffle some of the noise created by the air flow through the vacuum cleaner. In addition, some vacuum cleaners have employed separate muffler systems which are positioned after the dirt separation system and motor/fan units. Such muffler systems typically add cost, complexity and weight to the design of the vacuum cleaner. In addition, bagless vacuum cleaners typically are somewhat more expensive to produce than bag vacuum due to the extra material required to form the dirt cup. Thus, bagless vacuum cleaners incorporating a muffler system tend to be even more costly and complex.
What is needed therefore, is a muffler system for a bagless vacuum cleaner that overcomes the above-mentioned drawbacks.